I cracked the seat stay brace. No idea how, one day I turned my bike upside down and noticed it was cracked. Also my rear triangle was slightly bent to the side...

Several years ago, my friend did a simple wallride with stock steel handlebars that came on his complete, and the right side bent so bad it pretty much came off. Steel forks are terrible as well. Dropouts will bend like crazy!

Pretty much if you can, just avoid steel parts altogether. If you are a beginner and don't have much money to spend then I guess it would be alright.